Have to agree that Lee & Singh Ray are a bit 'specialist' in the pricing department. I think Lee have been doing a big marketing drive of late, lots of articles in the UK mags. Singh Ray have the (afaik) unique 'reverse' neutral grad, but otherwise I think the UK based hitech filters is plenty good enough .Link included below.
http://www.formatt.co.uk/stills-filters/products.aspx